In memories such as a synchronous dynamic random-access memory (SDRAM), errors may occur in data read from the memory by an influence of noise and the like occurring in the memory. The errors which have occurred are corrected by, for example, a memory controller that controls an access of the memory. For example, the memory controller counts the number of times of correcting errors for each address space allocated to the memory. The memory controller issues a fault notification to a diagnostic device in a case where the count value reaches a threshold value (for example, see Japanese Laid-open Patent Publication No. 2012-108726 and Japanese Laid-open Patent Publication No. 2010-170462). In a memory monitoring system that monitors a memory, errors are corrected in a case where a correctable error occurs, and the alarm is raised in a case where a frequency of errors occurring exceeds a predetermined threshold value (for example, see Japanese Laid-open Patent Publication No. 10-55320).
The occurrence of a correctable error may serve as a sign of an occurrence of an uncorrectable error. Therefore, if an occurrence of a situation in which the number of times of correcting errors reaches a predetermined threshold value is detected as a sign of the occurrence of an uncorrectable error, an occurrence of serious troubles such as system down is avoided. However, a method of causing a memory to perform an access operation having difficulty in the occurrence of an uncorrectable error, based on a situation in which a correctable error occurs has not been proposed.